feat: improve chapter ID matching with normalization and refined error handling.

Author: HideBa

packages/mcp-server/src/tools/read-chapter.ts

@@ -7,29 +7,66 @@ import type { ChapterIndexService } from "../services/chapter-index.js";
 import type { SpecLoader } from "../services/spec-loader.js";
 import type { ToolResult } from "../types.js";
 
+/**
+ * Normalize chapter ID for flexible matching:
+ * - lowercase
+ * - trim whitespace
+ * - replace spaces/underscores with hyphens
+ * - remove special characters
+ */
+function normalizeChapterId(id: string): string {
+  return id
+    .toLowerCase()
+    .trim()
+    .replace(/[\s_]+/g, "-") // spaces/underscores to hyphens
+    .replace(/[^a-z0-9-]/g, "") // remove special chars
+    .replace(/-+/g, "-") // collapse multiple hyphens
+    .replace(/^-|-$/g, ""); // trim leading/trailing hyphens
+}
+
 export async function handleReadChapter(
   params: ReadChapterInput,
   specLoader: SpecLoader,
   indexService: ChapterIndexService,
 ): Promise<ToolResult> {
+  const validChapters = await indexService.listChapterIds();
+  const normalizedInput = normalizeChapterId(params.chapter);
+
+  // Find matching chapter (exact or normalized match)
+  const matchedChapter = validChapters.find(
+    (chapterId) =>
+      chapterId === params.chapter || normalizeChapterId(chapterId) === normalizedInput,
+  );
+
+  if (!matchedChapter) {
+    return {
+      isError: true,
+      content: [
+        {
+          type: "text",
+          text: `Chapter '${
+            params.chapter
+          }' not found. Valid chapters: ${validChapters.join(", ")}`,
+        },
+      ],
+    };
+  }
+
   try {
-    const content = await specLoader.loadChapter(params.chapter);
+    const content = await specLoader.loadChapter(matchedChapter);
 
     return {
       content: [{ type: "text", text: content }],
     };
   } catch (error) {
-    // If chapter not found, provide helpful error with valid chapters
-    const validChapters = await indexService.listChapterIds();
-
     return {
       isError: true,
       content: [
         {
           type: "text",
-          text: `Chapter '${
-            params.chapter
-          }' not found. Valid chapters: ${validChapters.join(", ")}`,
+          text: `Error loading chapter '${matchedChapter}': ${
+            error instanceof Error ? error.message : "Unknown error"
+          }`,
         },
       ],
     };